Artificial filament



May 12, 1953 W 2,637,893

ARTIFICIAL FILAMENT Filed March 12, 1949 INVENTOR. G /1. BER T 5 HA w ,4 TTORNE Y5 Patented May 12, 1 953 UNITED STATES PATENT OFFICE ARTIFICIAL FILAMENT Gilbert Shaw, Middlebury, Vt.

Application March 12, 1949, Serial No. 81,126

1 Claim. (01. 2882) The present invention relates to improved fila- I ments utilizable, for instance, as bristles in the manufacture of push brooms, Whisks, brushes, and related articles. The invention relates more particularly to a filament which is artificially prepared, as contrasted with naturally occurring filaments such as vegetable fibres or animal hairs and bristles, said filaments of the invention being made of long chain, linear thermoplastic polymers the molecules of which have been oriented,

or made to lie generally in the direction of the with the invention, the same being realized and attained by means of the instrumentalities and combinations pointed out in the appended claim.

lhe invention consists in the novel parts, constructions, arrangements, combinations and improvements herein shown and described.

The accompanying drawings, referred to herein and constituting a part hereof, illustrate an embodiment of the invention, and together with the description, serve to explain the principles of the invention.

The invention has for an object the provision of an artificial filament having high qualities of stiffness, resiliency and durability making it particularly useful for use as bristles in brooms, brushes, and the like. The invention further provides a filament having increased surface area over conventional filaments of either natural or synthetic origin making it particularly useful for paint brushes and similar uses, for instance. Another object is the provision of a filament wherein the strength characteristics are retained but a substantially smaller mass of material is utilized than in conventional filaments, giving rise to savings in materials and a lighter weight in objects fabricated from the filaments.

Figs. 1 and 2 of the drawings illustrate two preferred cross sectional shapes which may be adapted for the synthetic filaments of the invention.

With the above stated and other objects in view the filament of the invention is made of a long chain linear polymer or copolymer such as, for instance, vinyl chloride-acetate or nylon, the molecules of which have been oriented, that is, made to lie generally in the direction of the length of the filament, in order to provide a filament of high modulus of elasticity and tensile strength. The filament is extruded from a suitable die so that the finished form of the filament provides a central filament portion and a plurality of filament web portions extending radially outwardly from the central portion. The web portions so provided are preferably of considerable radial extent, extending for at least several times the thickness of the central filament portion, sothat the construction of the filament is essentially that of several intersecting continuous web portions, the central portion of thefilament being merely the intersection of the several webs and having a cross sectional dimension of about the order of the width of such webs. In preferred forms of the filament all of the angles formed between adjacent surfaces of the webs by their intersection are equal, that is, the web portions are regularly positioned as radii in the body of the filament, and such web portions are preferably of substantially equal thickness and said thickness for each web portion is continuous. It will be apparent that filaments so fabricated will have maximum strength, stiffness and area characteristics for a minimum mass of material, and their use in brushes and brooms will provide maximum possible material economy.

It will be understood that the foregoing general description and the following detailed description as well are exemplary and explanatory of the invention but are not restrictive thereof.

Referring now in detail to the invention, Figs. 1 and 2 illustrate preferred cross sectional forms to be imparted to filaments in accordance with the invention, although such forms are given by way of example only, and other forms may be used. As shown in Fig. l, a cruciform cross sectional shape may be adopted for the filament wherein a central filament portion ii] is formed by the intersection of the radially extending web portions M, l2, l3 and M. The Web portions extend radially for distances which are several times the greatest thickness of the central portion [8, thus providing high strength in the filament with a minimum of material, and likewise providing a large total external surface. The angles a internally of the filament formed between the adjacent faces of the several web portions are preferably, though not necessarily, equal, and the several web portions are also preferably of the same thickness and of substantially uniform thickness throughout their lengths, providing uniformity in the construction and functioning of the filament.

As shown in Fig. 2 of the drawings, the filament may within the scope of the invention take a form having a Y cross section, wherein the central portion I5 is formed by the intersection of the three 3 web portions I6, I! and i8, and the arrangement and proportion of the elements is similar in principle to the embodiment of Fig. 1 just described.

In the formation of filaments of the invention any long chain linear thermoplastic polymer capable of being subsequently oriented may be used as the material for the filament depending upon the various properties which are desired in the finished pro uc't, and such pol'y'mer is extruded in accordance with known practices through spinnerets having shapes to impart the desired final form to the filament. In the case of filaments of the forms shown in Figs l and Z, for example, the bores or apertures of the spirinerets would have the forms of the cross sectional shapes of the finished filaments there shown.

After the filament is extrudedand solfdifiedit is then stretched in accordance with the method best suited to the partichlar material being used in l me mi n; fill ,I 1. the Po me scam-unwell lie .1. th .qi ectin q lt el n t .of...the filamentk giving a high m odulus of elasand..tensi a rene h. tgilaee I l d ..t'ions.. under which such stretching place -ivi11.-.hary in a,, cQrd& i=.Wit- ,t,h i t;iiria l.beine.use,d.afor inst ce lniylonlfil'am ts wil s re ch filw tens. to se e i ih f Y .inal n th. at .cpn t llgd t m ra re w i h L .Qm..ins a Q.m iY.- b $5. .fil men sc elrv nylg ar tre che l,ata tim r. 11'

.Zcr in anc n y mi s iihm ehf ni tmpsph .-f?m.. %h..we??? After e fil m t r riented the may in; accordance "withjk' I ract c h he is j .i lxii s nsebyr e smegma.. steam. befihiP or'dr meal s winkfi ifim. to a s aple er fijhe finished fila warrant "to 0.005 of 4 limited to the specific embodiments shown and described but departures may be made therefrom, within the scope of the accompanying claims, without departing from the principles of the invention and without sacrificing its chief advantages.

What I claim is:

A filament of substantially uniform cross-section throughoutdts length whichis particularly adapted for use as a brush bristle, 'saidfilament being formed from a long chain linear oriented stable thermoplastic polymer, said cross-section cornprising at least three fiat, thin, erect webs radiating at about equal angles from each other from a small center portion having a cross-sectionaldimension of about the order of the thicknessdf such web's,'whereby a high degree of stiffness and a great amount of surface is obtained with a minimum of polymer.

GILBERT SHAW.

rtf'iehc'es Cited in the file of this patent UN'I'TED 's'rA'rEs PATENTS @1 number "Name Date '1,7'73;969 Dreyfus et "a1. Aug-26,1930 @1002 ,1'53 Mendel May 21,1935 2,071,251 'Cai'others Feb. 16,1937 2,152j826 Spencer 1 -Ap'r. 4,4.939 "2,161,766 Rug'eleyet a1. June "6, L939 "2294;394 -Dra'emann Sept. 8,1942 2,433,325 Slaughter "Dec. 23,1947 255081799 Reis, "Jr -May-23, 0 EQREIGN A'PENTS mber... ic ilm i i Y mac gv phnandn Malawi-923 zsa so Italy l navjjaj'ifis 430,741 Germany "Jiixi-26;i926

"O HER REFERENCES r hlyvvbiir fsyhfihcic r ibr Thins"- 1931 revision. copy in' Div; 21. 

